There are many methods and apparatus purposed for the treatment of contaminated matter. Burying the material, incineration, vacuum extraction, and microbial mineralization are just a few available options. Burying the waste is commonly how radioactive and recalcitrant materials are treated. Solids are deposited in shallow trenches about three meters wide and between three and five meters deep. When the waste is filled to about one meter from the top of the trench, the trench is covered with earth. A large volume of heterogeneous contamination is produced by such waste which may continuously seep into the soil and water. Incineration is another available option. The purpose of incineration is to burn off the contaminants and leave only the clean soil. However, this may be a very expensive process and not very feasible if large volumes of soil need to be treated. Also, it may have pollution side effects of vapor and air pollution while the soil is being removed and moved to the incineration site. Soil Vacuum Extraction (SVE) is a simple and economical treatment method, however organochloric compounds in a concentration of several ppm or lower may not be readily removed when entrained within clays or loams. Further channeling is frequently found within a SVE system, further reducing the system's overall efficacy. Lastly, many compounds with poor Henry's Constants will not be efficiently removed via an SVE approach. This physical approach remediation process requires time in annual scale.
In order to solve the problems with the above-described methods, biological or in-situ oxidation processes have been devised. Critical to any in-situ injection process is the efficient delivery of materials to the targeted area or zone. Frequently materials may be injected by way of a cylindrical delivery rod with an expendable point. This point is pushed out to allow for pumped material to escape from the base of the injected point. In-situ remediation allows for petroleum hydrocarbon, chlorinated solvents, metals and radonuculi to be treated without any digging of the soil, so it can be performed where other treatment approaches may not be practical.
In order to perform in-situ treatments, an apparatus for delivery is needed. The most common and practical is a steel injection rod forced into the soil which causes preferential pathways when materials are forced from its terminus, often along the interface between the rod and the soil. These pathways prevent efficient application of remedial materials to the target zone. To alleviate this problem, a hollow injection rod with lateral discharge holes allows for liquids to be injected into the contaminated material and, when performed well, in-situ injections are not only practical but also very economical. However, problems exist, for example switching between feed systems cannot be accomplished without loss of pressure to the delivery line. The resulting vacuum causes the delivery pathways to close and results in reduced lateral distribution of delivered materials. It is because of these problems experienced from the vacuum developed downhole as pressure is released and reapplied that many remedial technologies fail when transitioned from laboratory to field application. This is a problem that is further exacerbated when it is desired to deliver dissimilar compounds sequentially for appropriate remediation to occur.